Unit and method for the treatment of shredder residues

ABSTRACT

In a method for sorting shredder residues of metal-containing wastes, e.g., vehicle bodies, the shredder residues are separated into a shredder light fraction and a non-ferromagnetic fraction (shredder heavy fraction). A system is arranged for sorting shredder residues of metal-containing wastes, e.g., vehicle bodies. At least parts of the primary material streams produced during the sorting of the shredder light fraction and the shredder heavy fraction in preliminary processes are fed to a common, main process for final processing, at least a ferromagnetic fraction, a fraction containing non-ferromagnetic metals, a granulate fraction, a fiber fraction, and a sand fraction being produced as end products.

FIELD OF THE INVENTION

The present invention relates to a method for sorting shredder residues of metal-containing waste for the purpose of producing fractions that may be used as materials and raw materials, and for energy, as well as to a system that may sort the shredder residues.

BACKGROUND INFORMATION

The shredding of scrapped vehicles for breaking down materials has been known for a long time. In carrying out the shredding method, method controls have been established in which the material mixture produced is divided up into different fractions. Thus, a so-called shredder light fraction (SLF) is initially separated from the material mixture produced, using a suitable suction device. The remaining fraction is subsequently separated into a ferromagnetic fraction (shredder scrap (SS)) and a non-ferromagnetic fraction (shredder heavy fraction (SHF)), using a permanent-magnet separator. The portion of the metallurgically fully usable shredder scrap-metal fraction is often approximately 50 to 75 wt. %. Existing designs generally provide for the shredder light fraction being disposed of as waste or burned in waste incinerators. It is characterized by both a large fraction of organics and a large fraction of fine-grained material. The heavy fraction, which is not able to fly and is not ferromagnetic, i.e., the shredder heavy fraction, is distinguished by a high percentage of nonferrous (NF) metals. Special sorting systems have been developed for recovering the different NF metals, where, however, the remaining residue of organic and inorganic, non-metallic components is generally disposed of as waste. In the following, shredder residues should be understood as all material streams from the shredding process, which may not be directly removed at the shredder as products that are metallurgically directly utilizable (shredder scrap).

Described in German Published Patent Application No. 44 37 852 is a method, in which the shredder light fraction is sorted to remove “unwanted components”, in particular copper and glass. In this context, the shredder residues are homogenized and mixed in a compulsory mixer with a fine-grained to superfine-grained material containing a magnetizable component, and the resulting mixture is conveyed through a magnetic separator. In this context, the metallic components of the shredder light fraction, which impede metallurgical use, can be separated out in this manner.

European Published Patent Application No. 0 863 114 describes the production of a permanently plastic, backfilling material for mines, by adding an adhesive component, a filler, and a salt solution to the shredder light fraction. This is intended to provide a pressure-resistant, permanently plastic body.

It is described in German Published Patent Application No. 197 42 214 that the shredder light fraction is shredded further and subjected to a thermal treatment. During or after shredding, metallic components should be sorted out and the remaining mixture of materials should be melted in a smelting reactor and converted to a “harmless” solid by cooling it.

In addition, European Published Patent Application No. 0 922 749 describes a method for processing the shredder light fraction, where the shredder light fraction is a calcined in a fluidized-bed gasifier amid the introduction of calcium carbonate.

In a further, thermal process, German Published Patent Application No. 197 31 874 describes the shredder light fraction being compressed again in a further step, and then shredded, homogenized, and reduced in water content, in order to be thermally utilized in a subsequent step.

European Published Patent Application No. 0 884 107 describes for the shredder light fraction being converted into a metal-free fraction having a shredding size of ≦20 mm, by shredding, classifying, and sorting it. The sorting of the shredder light fraction should result in a thermally utilizable fraction.

In addition to the utilization methods, it is conventional that the shredder light fraction can be subjected to a pretreatment, in which residual ferromagnetic fractions of iron, stainless steel, and aluminum are separated. Similar methods have also been used for sorting the shredder heavy fraction. Furthermore, it is conventional that polyolefins can be separated from this fraction.

What the methods have in common is, that they are each only designed for processing the shredder light fraction or the shredder heavy fraction. Joint processing is not provided. In addition, the methods are not suitable under the aspect of maximizing the degree of use in the order of material use, raw-material use, and energetic use. Against the background of increasing legal requirements (EU End of Life Vehicles Directive, EU Directive on Incineration of Waste, and others), as well as increasing landfill costs and requirements for the material to be landfilled, a higher utilization rate may be desirable. Thus, the German regulation on end of life vehicles of Apr. 1, 1998 provides for over 95% of a scrapped car by volume having to be utilized as of the year 2015. In addition, increased requirements from the EU Scrapped Car Guideline passed in September, 2000 specify that the fraction of material streams utilizable as materials and raw materials for mechanical and feedstock recycling should be increased to at least 85%. Thus, utilization excludes the use as energy only, e.g., in waste incinerators.

Therefore, it is an object of the present invention to provide a method and a system by which the shredder residues may be jointly processed, and separated in a mechanical sorting process into end products usable for materials, raw materials, and energy recovery. In particular, the joint processing may allow the portion of the unusable fraction to be reduced to less than 5% of the total weight of the scrap vehicle, and allow the portion of end products usable as materials or raw materials to be increased.

SUMMARY

According to an example embodiment of the present invention, this object may be achieved by providing a method for sorting shredder residues of metal-containing wastes, e.g., vehicle bodies, as described herein, as well as by providing a system for sorting the shredder residues as described herein. The method may provide that at least parts of the primary material streams formed during the sorting of the shredder light fraction and the shredder heavy fraction in preliminary processes may be supplied to a joint, main process for the final processing. At least a ferromagnetic fraction, a fraction containing nonferrous metals, a granulate fraction, a fiber fraction, and a sand fraction may be produced as end products. The prepared end products may either be utilized directly or, if desired, subsequently processed in further refining steps to form utilizable, high-quality products.

Fe, stainless steel, and Al portions broken down in a preliminary treatment may be separated from the shredder light fraction. This shredder light fraction may be:

-   -   broken down in a first shredding unit, and     -   subsequently separated into at least a ferromagnetic fraction         and a non-ferromagnetic fraction, using at least one magnetic         separator;     -   the non-ferromagnetic fraction is broken down in a second         shredding unit,     -   a fine-grained sand fraction is separated from this fraction,         using at least one classifier, and     -   the remaining fraction is separated into a fiber fraction and a         course-grained, heavy-material fraction in at least one         density-separation device.

The procedure, which includes the step-by-step breakdown of the shredder light fraction and the interposed method steps for separating out the particularly abrasive ferromagnetic components, may allow the operating costs to be kept low, e.g., in the case of the second shredding unit. In addition, the desired fiber and sand end products may already be separated out at this point of the overall process control for sorting the shredder residues. An example embodiment of the present invention may provide for a cellular-plastic fraction essentially made of polyurethane being additionally separated out in the preliminary process, using a suction device.

Each of the first and second shredding units may include a classifier positioned upstream from it for separating and supplying a sieved fraction. The diameter of the incoming fraction and the discharge of the shredding units may be adjusted to each other. This may allow the wear in the shredding units to be reduced.

In the preliminary process, the shredder heavy fraction may also be separated into at least an enriched fraction containing nonferrous metals, a heavy-material fraction, and a fine-grained sand fraction depleted in metals, using at least one metal separator and at least one classifier. In addition, it is possible for a high-density, residual fraction to be separated from the heavy-material fraction in at least one density-separation device. The shredder heavy fraction may be separated into different material streams from the standpoint of joint processing with the material streams previously produced in the preliminary process for processing the shredder light fraction.

In the main process, the material streams from the preliminary processes may be brought together in such a manner, that

-   -   the sand fractions are combined into a common sand fraction, and     -   the heavy-material fractions are combined into a common         heavy-material fraction, broken down by a shredding unit, and         separated by a density-separation device into the granulate         fraction and an enriched fraction containing nonferrous metals.

Therefore, the desired end products of sand, granulate, and the fraction containing nonferrous metals may be produced in this partial process step. The fractions containing nonferrous metals may then be subjected to for separating out light-metal fractions, heavier nonferrous-metal fractions, and other metal fractions, e.g., in a common sorting step, using suitable process steps such as sand flotation and optical sorting. The nonmetallic, residual fractions produced during the separation may be resupplied to the main process and/or the preliminary processes at suitable points, as a function of amount and composition.

Further, example embodiments of the method are described below.

Example embodiments of the system according to the present invention are described below. Regarding the aspects of the system according to the present invention, reference is made, e.g., to the above-mentioned explanations relating to the method according to example embodiments of the present invention.

The present invention is explained below in detail in an exemplary embodiment with reference to the corresponding drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flow diagram illustrating an overall view of the end products formed at specific times in the process of sorting the shredder residues.

FIG. 2 is a schematic flow diagram for the process control in the preliminary sorting processes and the main sorting process.

DETAILED DESCRIPTION

FIG. 1 is a flow chart of the times at which end products are produced according to an example embodiment of the method of the present invention, during the sorting of the shredder residues. In an upstream shredding process, metal-containing wastes, e.g., those of vehicle bodies, are initially broken down by a shredder in a shredding process. A light fraction capable of flying is subsequently separated off by a suction device (shredder light fraction SLF). The heavy material stream, which remains after the suction and is not capable of flying, is separated on a permanent-magnet separator, into a ferromagnetic and a non-ferromagnetic fraction. The ferromagnetic fraction is designated as shredder scrap SS and represents the primary shredder product, which may be used directly in metallurgy. The heavy, non-ferromagnetic fraction not capable of flying is referred to as shredder heavy fraction SHF. In a further pretreatment step, ferromagnetic components still present may be separated from shredder light fraction SLF by a magnetic separator. The remaining material stream of shredder light fraction SLF and shredder heavy fraction SHF are jointly separated as shredder residues into the desired end products.

To this end, the process control provides a preliminary process Pre_(L) for shredder light fraction SLF, a preliminary process Pre_(S) for shredder heavy fraction SHF, and a joint, main process SR_(M) for final processing of at least a part of the primary material streams produced in the preliminary processes Pre_(L), Pre_(S). According to the exemplary embodiment, fractions, which are predominantly made up of highly pure iron Fe, stainless steel, fiber, sand, granulate, cellular plastic PU, and a residue to remove, are formed as end products. In addition, a nonferrous-metal fraction NF may be separated out, which, in turn, appropriate process control allows to be divided up into fractions having heavier nonferrous metals Cu/brass, light metals Al/Mg, and other metals. Except for the residual fraction, the end products formed may be used metallurgically, as materials, as raw materials, or for energy recovery.

FIG. 2 is a schematic flow diagram of the essential components of the system for sorting the shredder residues, as well as the respective intermediate or end products produced at these components during the process control. In order to retain an overall view, the end products produced during the process are arranged in the center. Preliminary process Pre_(L) for sorting shredder light fraction SLF is schematically illustrated on the left part of the drawing, preliminary process Pre_(S) for sorting shredder heavy fraction SHF is schematically illustrated on the right part of the drawing, and main process SR_(M) is schematically illustrated in the center of the lower part of the drawing.

Shredder heavy fraction SHF is initially subjected to two-stage Fe and stainless steel separation by permanent magnet separator PM_(H) 1. After Fe and stainless steel separation, the residual stream is classified, and fractions NF_(H) containing heavier nonferrous metals are separated out. This may be accomplished, for example, by initial classification into different fractions, e.g., greater than and less than 20 mm, and by separately feeding each fraction to metal separator MS_(H) 1. It is possible to have additional classification steps. In this context, it may be provided to achieve as clean a material separation as possible into fractions NF_(H) containing heavier nonferrous metals, and remaining fractions NM_(H) depleted in metals. Classifier C_(H) 1 also provides for fractions NM_(H), which are depleted in metals and have a particle diameter, e.g., <6 mm, being separated out as a sand fraction Sand_(H).

Remaining coarse-grained fraction NM_(H) depleted in metals is subsequently separated by a density-separation device D_(H) 1 into a heavy-material fraction HG_(H) and a high-density residual fraction Residue. This may prevent materials, which are still highly abrasive and have sharp edges, such as balls of high-grade steel, from being present in the shredding chamber during the further treatment of heavy-material fraction HG_(H) in downstream shredding units. In addition, a metal separator may be installed at this position, in order to separate out the last solid, wear-promoting, metal contaminants. In summary, preliminary process Pre_(S) accordingly may yield an iron fraction Fe, a stainless steel fraction, a fraction NF_(H) containing heavier nonferrous metals, a sand fraction Sand_(H), and a heavy-material fraction HG_(H).

In preliminary process Pre_(L), a cellular-plastic fraction PU, which is predominantly made up of the polyurethane that is highly capable of flying, is initially separated from shredder light fraction SLF in suction device SU_(L) 1. The separated pieces of cellular plastic are pneumatically transported into a press container, where they are automatically compressed. This fraction may be directly utilized or optionally undergo a further refining step.

The remaining fraction is broken down in a first cominution unit CO_(L) 1, and indeed in such a manner, that the discharge of unit CO_(L) 1 contains particles having a diameter <50 mm. In order to keep the load on shredding unit CO_(L) 1 as small as possible, a classifier may be positioned upstream from it, in order to separate out and supply a fraction having a diameter >50 mm. An iron fraction Fe and a stainless steel fraction are separated from the shredded fraction by a permanent magnet separator PM_(L). Remaining non-ferromagnetic fraction NFM_(L) is supplied to a second shredding unit CO_(L) 2, in which the material is broken down further. In this context, the discharge of shredding unit CO_(L) 2 is arranged to be <10 mm. In this case, the infeed of shredding unit CO_(L) 2 may also be limited to a fraction having a diameter >10 mm, using a classifier.

In an additional classifier C_(L) 1, a fine-grained sand fraction Sand_(L) is separated from the now effectively broken-down, non-ferromagnetic fraction NFM_(L). The particle size of sand fraction Sand_(L) may be set to <4 mm. The remaining fraction is subjected to air sifting and density separation in a suitable device D_(L) 1. In device D_(L) 1, a light fraction made up of fiber is blown over a heavy-material trap. Due to being previously transported on a vibrating conveyor, the heavier material has already settled to the bottom, so that the underlying heavy fraction automatically falls down into a heavy-material discharge (heavy-material fraction HG_(L)). In summary, the end products and intermediate products of cellular-plastic pieces PU, iron Fe, stainless steel, Sand_(L), and heavy material HG_(L) may be provided in preliminary process Pre_(L). The dust and sludges containing heavy metals and organic substances are fed to residual fraction Residue during the treatment in shredding units CO_(L) 1 and CO_(L) 2.

In main process SR_(M), sand fractions Sand_(L), Sand_(H) are initially combined into a common sand fraction Sand. This fraction may optionally undergo a further refining step not represented here.

Heavy-material fractions HG_(L) and HG_(H) are also combined into a common heavy-material fraction HG. These are subsequently broken down again in a further shredding unit CO_(M) 1. The discharge of shredding unit CO_(M) 1 is arranged to be <8 mm. Shredding unit CO_(M) 1 may take the form of an impeller breaker, in order that the material is optimally broken down at this position. After the shredding, density separation takes place on air-settling tables (density-separation device D_(M) 1). The light fraction separated off is predominantly made up of plastic in granular form. In an additional refining process, the granulate may optionally be separated into further, utilizable end products. Remaining, heavy fraction NF_(M) may be mostly made up of heavier nonferrous metals, mainly copper strands. Therefore, fraction NF_(M) may already be removed from the process at this point, but it may also be combined with heavier nonferrous-metal fraction NF_(H) into a common fraction NF, and be jointly sorted.

Fraction NF containing nonferrous metals may essentially be sorted by a sand flotation system SF1 and an optical sorter OS1. Sand flotation allows a light-metal fraction predominantly made up of aluminum and magnesium to be separated from a heavy-metal fraction in a dry mechanical manner. It should be noted that the sand used here as a separation medium has nothing to do with the fraction “Sand” separated from the shredder residues. The heavy metals sink into the sand bed, while the light metals float on the sand bed. An upper stream containing light metals and the lower screen enriched with the heavy metals are separated by a separating partition. The metal concentrates are separated again from the separating medium, Sand, in a process step belonging to sand flotation. Separated aluminum and magnesium fraction Al/Mg may optionally be separated to a further extent.

The separated heavy fraction (in particular zinc, copper, brass, lead, and possibly V4A steel) is separated into nonferrous metals copper/brass, as well as other metals, using optical sorter OS1. Depending on the amount and composition, any nonmetallic residues produced here may be fed in at a suitable position, such as, in this case, into preliminary process Pre_(L). In summary, an Al/Mg fraction, a Cu/brass fraction, a fraction having other metals, and a granulate fraction are provided in the main process SR_(M) having subsequent nonferrous-metal separation.

Reference Symbol List

-   SU_(L) 1 suction device (separation of cellular-plastic fraction) -   Al/Mg light-metal fraction -   Cu/brass heavier nonferrous metal fraction -   D_(M) 1, D_(L) 1, D_(H) 1 density-separation devices -   Fe iron fraction -   Fiber fiber fraction -   Granulate granulate fraction -   C_(L) 1, C_(H)l classifiers -   MS_(H) metal separator -   NF, NF_(M), NF_(L), NF_(H) fractions containing nonferrous metals -   NFM_(L) non-ferromagnetic fraction -   NM_(H) fraction depleted in metals -   OS1 optical sorter -   PM_(L) 1, PM_(H) 1 permanent-magnet separator -   PU cellular-plastic fraction -   Residue residual fraction -   Sand, Sand_(L), Sand_(H) sand fractions -   SF1 sand flotation system -   HG, HG_(L), HG_(H) heavy-material fractions -   SLF shredder light fraction -   Other metals fraction having other metals -   SR_(M) main process -   SS shredder scrap -   SHF shredder heavy fraction -   Pre_(L) preliminary process for the shredder light fraction -   Pre_(S) preliminary process for the shredder heavy fraction -   CO_(L) 1, CO_(L) 2, CO_(M) 1 shredding units 

1. A method for treating shredder residues of metal-containing waste, comprising: separating the shredder residues into a shredder light fraction and a non-ferromagnetic fraction; separating each of the shredder light fraction and the non-ferromagnetic fraction into additional material streams in separate preliminary processes; and feeding at least a part of one of the material streams of a first one of the preliminary processes and at least a part of the material stream of a second one of the preliminary processes to a joint main process for further processing; wherein the first one of the preliminary processes includes: breaking down the shredder light fraction in a first shredding unit; and subsequently separating the shredder light fraction into at least an iron-containing fraction and a non-ferromagnetic fraction by at least one magnetic separator.
 2. The method according to claim 1, wherein the iron-containing fraction includes a ferromagnetic fraction.
 3. The method according to claim 1, wherein the first one of the preliminary processes includes: breaking down the non-ferromagnetic fraction of the shredder light fraction in a second shredding unit; separating a fine-grained sand fraction from the broken-down non-ferromagnetic fraction by at least one classifier; and separating a remaining fraction into at least one of a fiber fraction and a coarse-grained, heavy-material fraction in at least one density-separation device.
 4. The method according to claim 3, wherein the classifier is configured to separate and supply a fraction having a second diameter arranged upstream from the second shredding unit, a discharge of the second shredding unit including a diameter less than the second diameter.
 5. The method according to claim 4, wherein the second diameter is greater than 10 mm.
 6. The method according to claim 4, wherein the diameter of the discharge of the second shredding unit is less than 10 mm.
 7. The method according to claim 3, wherein the fine-grained sand fraction separated by the at least one classifier has a diameter less than 4 mm.
 8. The method according to claim 1, wherein the first one of the preliminary processes includes separating a cellular-plastic fraction from the shredder light fraction by a suction device.
 9. The method according to claim 1, wherein a classifier configured to separate and supply a fraction having a first diameter is arranged upstream from the first shredding unit, a discharge of the first shredding unit having a diameter less than the first diameter.
 10. The method according to claim 9, wherein the first diameter is greater than 50 mm.
 11. The method according to claim 9, wherein the discharge of the first shredding unit is less than 50 mm.
 12. The method according to claim 9, further comprising: conveying a small fraction of the classifier past a respective shredding unit; and treating at least a portion of the small fraction as a respective discharge.
 13. A method for treating shredder residues of metal-containing waste, comprising: separating the shredder residues into a shredder light fraction and a non-ferromagnetic fraction; separating each of the shredder light fraction and the non-ferromagnetic fraction into additional material streams in separate preliminary processes; and feeding at least a part of one of the material streams of a first one of the preliminary processes and at least a part of the material stream of a second one of the preliminary processes to a joint main process for further processing; wherein the preliminary process includes separating the non-ferromagnetic fraction into at least two of an enriched fraction including nonferrous metals, a heavy-material fraction and a fine-grained sand fraction depleted in metals.
 14. The method according to claim 13, further comprising separating a high-density, residual fraction from the heavy-material fraction in at least one density-separation device.
 15. The method according to claim 13, wherein the fine-grained sand fraction has a diameter of less than 6 mm and is separated out by a classifier.
 16. The method according to claim 13, further comprising combining metal fractions to form a common metal fraction.
 17. The method according to claim 16, further comprising separating at least one of a light-metal fraction and a heavy fraction from the common metal fraction in a sand-flotation unit.
 18. The method according to claim 17, further comprising optically sorting the heavy fraction to separate out at least one of a nonferrous-metal fraction and another metal fraction.
 19. The method according to claim 17, further comprising feeding a nonmetallic, residual fraction produced during the separation to at least one of the main process and the preliminary processes at suitable points as a function of amount and composition.
 20. A method for treating shredder residues of metal-containing waste, comprising: separating the shredder residues into a shredder light fraction and a non-ferromagnetic fraction; separating each of the shredder light fraction and the non-ferromagnetic fraction into additional material streams in separate preliminary processes; and feeding at least a part of one of the material streams of a first one of the preliminary processes and at least a part of the material stream of a second one of the preliminary processes to a joint main process for further processing; wherein the preliminary process includes separating the non-ferromagnetic fraction into an enriched fraction including nonferrous metals, a heavy-material fraction and a fine-grained sand fraction depleted in metals.
 21. A method for treating shredder residues of metal-containing waste, comprising: separating the shredder residues into a shredder light fraction and a non-ferromagnetic fraction; separating each of the shredder light fraction and the non-ferromagnetic fraction into additional material streams in separate preliminary processes; and feeding at least a part of one of the material streams of a first one of the preliminary processes and at least a part of the material stream of a second one of the preliminary processes to a joint main process for further processing; wherein the main process includes bringing together material streams from the preliminary processes so that sand fractions are combined to form a common sand fraction and so that heavy-material fractions are combined to form a common heavy-material fraction.
 22. The method according to claim 21, further comprising at least one of breaking down by a shredding unit and separating by a density-separation device the common heavy-material fraction.
 23. The method according to claim 22, wherein a discharge of the shredding unit is less than 8 mm.
 24. The method according to claim 21, further comprising at least one of breaking down by a shredding unit and separating by a density-separation device the common heavy-material fraction into at least one of a granulate fraction and an enriched fraction containing nonferrous metals. 